Watercraft are known as are watercraft that have alternative support or buoyancy systems which rely on mechanisms other than the hull of the watercraft. It is generally assumed in marine architecture that the hull of a vessel is also the component of the vessel which rests on or partially submerged within the water.
Alternatives to this are vessels such as hydrofoils and the like which use shaped foils to create lift to remove the bulk of the watercraft hull from the water during travel.
Examples of attempts in the art to provide such a buoyancy system are contained in U.S. Pat. No. 3,237,582 which teaches a concave disc hydrofoil and U.S. Pat. No. 4,061,104 which teaches a watercraft with pairs of rotary members having foil shaped peripheral portions extending into the water at an acute angle with respect to the water surface and are movable both axially and angularly to achieve optimum lift consistent with the vessel's speed.
The inventor of the present invention has also been active in this area previously in the form of U.S. Pat. No. 5,638,766. This patent disclosed a water craft comprising a hull having a main longitudinal axis defining a direction of travel of the craft, a plurality of discs mounted at respective opposed sides of the main longitudinal axis to and below the hull and in combination having sufficient buoyancy to support the hull above the water, each disc comprising an essentially circular skimming surface adapted to skim upon the water as the craft moves at speed, each disc being adapted to rotate about a rotational axis which projects laterally at an acute angle with respect to a horizontal reference plane such that the skimming surface faces downwardly and outwardly with respect to the longitudinal central axis of the hull; wherein the discs are pivotably mounted to the hull by way of a ball joint, the ball joint comprising a ball affixed to or integrally formed with a leg extending from the hull, the ball extending into a socket formed within the disc and being retained therein by a retention flange secured to the disc.
It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.